Counterboring tool



June 29 1926.

E. GAIRING COUNTERBORING TOOL Filed May 25 1924 HNVENTOR ATTORNEY Patented June 29, 1926.

UNITED .STATES EMIL GAIRING, or nn'mor'r, MICHIGAN.

I COUNTERBORING 'roon.

Application filed May 23, 1924. Serial No. 715,465.

My invention relates to boring tools and more particularly counterboring tools, shown in the accompanying drawings and described in the following specification and claims.

6 This invention consists primarily in a device of simple and inexpensive construction in which the shank of a cutting tool is secured in the socket of the holder, the cutting tool being formed with-a tapering shank 10 adapted to extend into the correspondingly shaped socket portion of the holder to axially align it with'the latter and to provide a driving connection therewith. The tool is also formed with a central bore to receive a screw threaded bolt or pilot rod, having an enlarged head overlapping the end of the tool, the bolt extending through a central bore in the tool into engagement with a removable hexagonal nut fitted to the correspondingly shaped socket walls of the holder,the construction being such that as the tool is worn away through grinding or use the threaded end of the pilot rod may project beyond the nut into a central bore in the holder designed to receive it.

A further object of the invention is to provide thetapered end of the shank with a hexagonal or other suitably shaped projection adapted to fit into a correspondingly shaped socket portion of the tool holder, whereby an additional driving connection between thetool and holder is obtained Another feature of the invention consists in providing the holder with a transverse bore extending through the walls of the socket above the end of the tool shank, whereby upon removal of the pilot rod or bolt a pin may be driven transversely through the holder. to force the tool from the socket when it is desired to remove the tool for sharpening or replacement.

With the foregoing and other objects in view which will appear as the description proceeds the invention further resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed it being understood that changes may be made in the precise embodiment of the invention herein disclosed without departing from the spirit of the same.

In the drawings accompanying this specification:

Figure 1 is a central vertical sectional view taken on or about line 55 of Figure 1,

looking toward the split ring and nut supported in the socket of the holder.

Figure 6'is a cross-sectional view through the holder taken on or about line 66 of Figure l, looking in the direction indicated by the arrows.

Referring now to the letters of reference placed upon the drawings:

A denotes a socket holder for. a boring tool having a tapering shank A adapted for insertion in a suitable chuck or other driving meansnot shown. The interior walls of the socket portion of the holder for a portion of their length are preferably hexagonal in cross-section to receive'and embrace a corre spondingly shaped nut B secured against dislodgment in the holder bya split expansion ring C inserted in a peripheral groove A in the wall of the socket, the ring over- 1 lapping the corners of the nut thus securing the latter against dislodgment.

D indicates a cutting tool having a plurality of cutting flutes D and arelatively short tapering shank D adapted to enter the correspondingly shaped end of the tool holder. The cutting tool is provided with a central bore to receive apilot rod or bolt E having an enlarged head E overlapping the tool and threaded at its oppositeend to engage the nut B .the end of the tool shank projecting beyond its tapered portion is preferably hexagonal in cross-section as indicated at D to fit the correspondingly. shaped hexagonal socket of the tool holder, thereby providing a positive driving connection between the tool and the holder.

F designates a transverse hole extending through the walls in the socket of the tool. holder beyond the end of the tool shank when inserted in the latter. The hole is provided for the passage of a pin adapted to be driven through the holder to release the shank of the tool from the socket portion.

Having now indicated the several parts by reference letters theconstruction and operation of the device will be readily understool.

The, tapering shank of the tool coordi-.

nates with the like tapering end of the tool socket to insure precision in centralizing the cutting tool with the axis of the tool holder, thus insuring accuracy in production and an extended driving connection between the shank of the tool and the socket of the hole in thewalls of the socket, which hearing upon the end of the shank forces the tool from the holder as will be readily understood. a

Having thus described my invention what I claim:

1. In a device of the character. described,

the combination of a cutter and a holder therefor, said holder having a long tapering bearing portion at the outer end and provided with a long polygonal driving portion at the inner end having a plurality of flat walls are provided at a point intermediate the ends of the flat walls with a transverse opening adapted to receive a cutter releasing element, the socket having an annular groove adjacent the inner side of the cutter, said cutter having a tapering shank fitting the tapering bearing portion of the socket of the holder and provided with a projecting end terminating at the transverse opening and having a plurality of flat walls adapted to coordinate with the corresponding flat walls of the socket holder, a removable nut lodged in the socket of the tool holder and located between the inner end of the socket holder and said annular roove and having flat side walls coordinating with the said flat walls of the socket, a

split ring lodged in the-said annular groove formed in the socket wall of the tool holder at the inner side of said transverse opening and overlapping. said nut at the outer corners thereof, and securing the nut against dislodgment, and a bolt or pilot rod extend ing through a central bore in the cutting tool and having an enlarged head overlapping the latter, its opposite end being threaded to engage the nut, whereby the tool is held in the socket of the holder.

2. In a device of the character described, the combination of a cutter and a holder therefor, said holder consisting of a single piece andhaving a socket provided at the outer end with a long tapered bearing portion and having at its inner end a long driving portion provided with a plurality of fiat walls, said cutter having a tapering shank fitting the tapering bearing portion of the socket of the holder and provided with a projecting end having aplurality of flat walls fitting the fiat walls of the socket of the holder, a removable nut also fitting the fiat walls ofthe socket of the holder and lodged in the innerend of the socket in spaced relation with the cutter, and a bolt extending through the cuttin tool and having an enlarged head engaging the cutting tool at the outer end thereof, the inner end of the bolt being threaded and engaging the nut.

3. In a device of the character described, the combination of a cutter and a holder therefor, said holder consisting of a single piece and provided with a socket having a plurality of fiat walls at its inner portion, said cutter having a shank fitting the socket and provided with a projecting portion having a plurality of flat faces fitting the flat walls of the socket and holding the cutter against relative movement, a nut removably lodged in the socket and having flat faces fitting the flat faces of the said socket, and a bolt passing'centrally through the cutter and having an enlarged head at its outer end to engage the outer end of the cutter and having a threaded inner portion engaging the nut.

In testimony whereof, I sign this specification.

, EMIL GAIRING. 

